[Characteristics of genesis and development of peritoneal adhesion by different causes: experiment with rats].

Objective: To investigate the characteristics of genesis and development of peritoneal adhesion by different causes.

Methods: 236 rats underwent laparotomy with their vermiform processes lifted up and were randomly divided into 5 groups: Group A (control group), with the vermiform process exposed to air for 5 min, Group B, with the vermiform process smeared with talcum powder; Group C, with the vermiform process scraped by scalpel; Group D, with the tip of vermiform process stabbed by needle so as to squeeze the contents of intestine to cause infection; and Group E, with the artery of vermiform process ligated. Then the abdominal incision was sutured. 1, 2, 4, and 6 weeks after the treatment 11-12 rats from each group were randomly to undergo laparotomy. The degree of adhesion was graded blindly by Bhatia's method. The vermiform process was resected to undergo pathological examination and examination of the level of organ hydroxyproline (OHP) was detected.

Results: (1) At different time points the adhesive grades of Groups B-E were all significantly higher than that of Group A (all P < 0.05) and the adhesive grades of Groups B and D were both significantly higher than those of Groups C and E (both P < 0.05). There were no significant differences in the adhesive degree 1, 2, and 4 weeks after the treatment between Groups C and E, however, the adhesive degree of Group E was significantly lower than that of Group C (P < 0.05). (2) There were not significant differences in the OHP levels at any time points in Group A (all P > 0.05). There were not significant differences in the OHP levels 1, 2, and 4 weeks after the treatment (all P > 0.05), and the levels 8 weeks after the treatment were all significantly lower than those 1, 2, and 4 weeks after the treatment (all P < 0.05) in Groups B, D, and E. In Group C the OHP level 2 weeks after the treatment was 0.275 +/- 0.031 microg/mg protein, significantly lower than that 1 week after (0.221 +/- 0.036 microg/mg protein, P < 0.05), and the OHP level 8 weeks after the treatment was 0.254 +/- 0.039 microg/mg protein, significantly lower than those 1, 2, and 4 weeks after (all P < 0.05). The OH levels 1, 2, and 4 weeks after the treatment of the 4 experimental groups were all significantly higher than that of the control group (all P < 0.05). 8 weeks after the treatment the level of OHP of Groups B was significantly higher than that of Group A (P < 0.05), however, the OHP levels of Group C, D, and E had all decreased to almost similar to that of Group A (all P > 0.05). (3) The adhesive degrees of Groups C and E were significantly positively correlated with the OHP level (both P < 0.05), however, the adhesive degrees of Groups B and D were not significantly correlated with the OHP level (both P > 0.05). The adhesive degrees 1, 2, and 4 weeks after the treatment of the 5 groups were all significantly positively correlated with the OHP levels (all P < 0.05, however, the adhesive degrees 8 weeks after the treatment of the 5 groups were all not significantly correlated with the OHP levels (all P > 0.05). (4) The main pathological changes of Group B were foreign body granuloma reaction and fibroplasia in Group B and unspecific inflammatory reaction and fibroplasia in Groups C, D, and E.

Conclusion: Abdominal adhesions resulting from different causes show different characteristics. The abdominal adhesion caused by foreign bodies and that caused by infection are relatively severe and more difficult to recover than those caused by injury and ischemia. It is more reliable to use OHP level as a marker of abdominal adhesion in the early stage.